1. Technical Field
The present invention relates to a vibrator element and a vibrator, an oscillator, and an electronic device that include the vibrator element.
2. Related Art
Generally, as a vibrator element, a tuning fork type-vibrator (hereinafter, referred to as a vibrator element) is known which has a first face arranged toward a first direction, three arms (hereinafter referred to as vibrating arms) arranged in a second direction intersecting the first direction, piezoelectric elements (excitation electrodes) each one disposed on the first face of each vibrating arm, a base portion that connects one ends of the vibrating arms (for example, see JP-A-2009-5022).
Recently, in accordance with the progress in the miniaturization of the vibrator element, there is a problem in that the Q value (a dimensionless number representing the vibration state, and the higher this value is, the more stable the vibration is) decreases.
A vibrator element disclosed in JP-A-2009-5022 is configured such that the vibrating arms have a vibration form (out-of-plane vibration mode) of flexural vibration in a direction perpendicular to the first face and achieves suppression of the decrease in the Q value (in other words, the improvement of the Q value) by configuring the vibrating direction of a center vibrating arm and the vibrating direction of the vibrating arms located on both sides to be opposite directions (inverse phases) and balancing the vibration of both parties.
However, in the embodiment of the vibrator element, since the arm widths of the three vibrating arms are formed to be the same, in a case where the vibration amplitudes of the three vibrating arms are the same, based on the principle of conservation of momentum and the like, there is a concern that the vibration of the center vibrating arm and the vibration of the vibrating arms located on both sides may not be sufficiently balanced.
Accordingly, in the vibrator element, since the vibration energy of the vibrating arms can be easily delivered to the base portion, there is a concern that the Q value may decrease due to the leakage of the vibration energy into an external member through the base portion.